We basically age bucks by general body characteristics like most hunters, or we have a few that we have had history with. But honestly, I am not sure any of us really care that much. The jaw bone of my best buck has sat in my basement I think for 3 years and I am not 100% certain I could even find it. Whether that 4pt is 10 or 3-4yrs, its still the same cool buck and it ain't getting any older. If we did care, I agree Dan that a lab would be the best option.